The hypostasis of the 3D display is to produce stereoscopy with a parallax, namely, to make a left-eye image be seen by the left eye of a person, and a right-eye image be seen by his right eye. Where, the left-eye and right-eye images are a pair of stereoscopic images having a parallax. Current 3D display technologies can be mainly classified into a glasses mode and a naked-eye mode. As regards the glasses mode 3D display technology, it is inevitable that a user has to wear glasses, and long-time watching will fatigue eye and will degrade the comfort level of watching. The naked-eye mode 3D technology does not require a user to wear glasses, and will become a mainstream of the 3D display technology in the future.
A parallax barrier method is a naked-eye 3D display technology that is commonly used, and as shown in FIG. 1, a naked-eye 3D display device with a parallax barrier includes a display unit 1 and a parallax barrier 2 disposed in correspondence with the display unit 1. The parallax barrier 2 is an optical device with periodically arranged light transmitting and light shielding stripes.
The display principle of the parallax barrier 2 is shown in FIG. 2. The display unit 1 is classified into two portions, i.e., pixels denoted by left-oblique lines, with which a right-eye image is displayed, and pixels denoted by right-oblique lines, with which a left-eye image is displayed, and one parallax barrier 2 is placed between the display unit 1 and a viewer. Light shielding regions of the parallax barrier 2 will be used to shield the right-eye image for the left eye of the viewer, and to shield the left-eye image for his right eye, so that the viewer sees merely the left-eye image with the left eye and sees merely the right-eye image with the right eye through light transmitting regions. Thereby, a 3D effect is attained.
In order to realize the 2D/3D switch, a liquid crystal slit grating is usually employed as the parallax barrier. The liquid crystal slit grating generally adopts a liquid crystal panel of a TN mode (namely, a liquid crystal mode for nematic liquid crystals in which the twisted angle of liquid crystal molecules is 90 degrees). When being energized, the liquid crystal slit grating turns to be a slit grating with alternating light transmitting and light shielding stripes, so that the 3D display can be achieved; and when being not energized, the liquid crystal slit grating is pervious to light as a whole, so that the 2D display can be conducted.
FIG. 3 is a structurally schematic view showing a liquid crystal slit grating in prior art. The liquid crystal slit grating includes two substrates (upper and lower substrates) and liquid crystal filled between the two substrates. On a lower surface of its upper substrate, a plurality of transparent electrodes 2-1, which are arranged separately with a certain distance therebetween, are provided, and on an upper surface of the lower substrate, a whole layer of transparent electrode 2-2 is provided in correspondence with the transparent electrodes 2-1. As shown in FIG. 4, provided that a width of a light shielding region of the liquid crystal slit grating is c, and a width of a light transmitting region is d, then a width of each of the transparent electrodes 2-1 on the lower surface of the upper substrate is usually c, and an interval between adjacent transparent electrodes 2-1 is d.
In the course of fabricating such a parallax barrier, it is necessary that on each of the two substrates, a transparent electrode be deposited one time, and exposure, development and etching be conducted at least one time, so as to form a pattern shown in FIG. 4. Thus, the fabrication cost is relatively high. Furthermore, because two transparent electrodes are formed on two substrates, respectively, a anisotropic conductive adhesive is required to electrically communicate the transparent electrode formed on one of the two substrates with a leading wire on the other of the two substrates, and thus, the fabrication cost is further increased.